The use of drainage trenches to direct water away from a building, and thus to prevent water from seeping into the building, has been known for many years. In some cases perforated or slotted drain tiles are used in the trenches, with the trench being provided around the inside and/or outside perimeter of a building to form a pipe line which relieves hydrostatic pressure by collecting and diverting water away from the building, such as to a sump pump or a drainage field. Such systems are frequently referred to as French drain tile systems.
The drain tiles typically comprise perforated or slotted pipe sections with sufficient perforations or slots to collect and divert water. The tiles are used to at least partially fill the trench and keep dirt and debris from filling the trench and restricting the flow of water. The tiles may also help support a covering material, such as concrete or another flooring material.
In some cases the tiles are positioned in a bed of river rock, gravel or crushed stone (referred to collectively in this disclosure as natural gravel, rock, or stone), which allows water to flow into the tiles and keeps dirt from clogging the perforations/slots. The gravel also provides a supporting substrate for concrete, etc., that may be added to cover the drain tiles from above.
In other water drainage systems gravel may be used to facilitate water flow even when perforated drain tiles are not used. In such systems another channel material may be used, or the trench may be filled only with gravel.
While the use of gravel to surround the drain tile provides advantages in terms of allowing good water flow and the ability to hold the tile in place, it also has disadvantages. For example, because the amount of gravel used in a particular job is large, heavy equipment such as dump trucks and front loaders are generally required to transport and handle the stone. In addition, transporting the gravel around the job site (e.g., into a basement) requires substantial physical labor and adds significant cost to the job.
Similarly, the use of gravel in tile-free systems also has disadvantages, including difficulty in transporting, storing, and using the gravel, as well as its propensity for introducing dirt or other contaminants to the drain area.
A need therefore exists for materials and methods for use in water drainage systems when it is desired to avoid the disadvantages of natural gravel. The present invention addresses that need.